Related Cos., in partnership with New York City pension funds, is ramping up its multifamily moves, with the $112.5 million purchase of a 20-building Bronx portfolio – the largest package to change hands in the borough this year, sources told The Real Deal.

The portfolio contains 737 apartments spread throughout the North, West and South Bronx. In a statement, a spokesperson for Related confirmed the portfolio buy and said the firm’s Related Fund Management arm and the pension funds plan to preserve the units in a long-term hold as workforce housing.

The buildings are largely low-rise walkups with rent-stabilized units. They are in a mix of working-class and middle-class neighborhoods such as Soundview, Wakefield, High Bridge and Fordham.

A group of private Brooklyn Heights-based investors known as Eastern Capital Partners acquired the properties in several transactions over the past five years, records show.

Last year, Related and the city pension funds to acquire 35 rental buildings from Stanley Wasserman’s SW Management for $270 million. Over the summer, the development giant behind the Hudson Yards megaproject scooped up a 10-building, Brooklyn-and-Queens package from Silvershore Properties and three formerly distressed buildings in Marine Park.

The Bronx is undergoing something of a residential renaissance, with more than 11.5 million square feet of residential real estate under development borough-wide, according to a TRD analysis in September.